Another hour passed, but there was still no sign of the air-ship. This of course was to be expected, for they had still another seventy-five miles or so to go before the rendezvous was reached.
"Steamer to the south'ard!" sang out the man on the forecastle, just as Tremayne came on deck after an attempt at a brief nap. He picked up his glass, and took a good look at the thin cloud of smoke away on the southern horizon.
From what he could see it was a large steamer, and was coming up very fast, almost at right angles to the course of the Lurline. Fifteen minutes later he was able to see that the stranger was a warship, and that she was heading for Queenstown. She was therefore either a British ship attached to the Irish Squadron, or else she was an enemy with designs on the liners bound for Liverpool.
In either case it was most undesirable that the yacht should be overhauled again. Any mishap to her, even a lengthy delay, might have the most serious consequences. A single unlucky shell exploding in her engine-room would disable her, and perhaps change the future history of the world.
Tremayne therefore altered her course a little more to the northward, thus increasing the distance between her and the stranger, and at the same time ordered the engineer to keep up the utmost head of steam, and get the last possible yard out of her.
The alteration in her course appeared to be instantly detected by the warship, for she at once swerved off more to the westward, and brought herself dead astern of the Lurline. She was now near enough for Tremayne to see that she was a large cruiser, and attended by a brace of torpedo-boats, which were running along one under each of her quarters, like a couple of dogs following a hunter.
There was now no doubt but that, whatever her nationality, she was bent on overhauling the yacht, if possible, and the dense volumes of smoke that were pouring out of her funnels told Tremayne that she was stoking up vigorously for the chase.
By this time she was about seven miles away, and the Lurline, her twin screws beating the water at their utmost speed, and every plate in her trembling under the vibration of her engines, rushed through the water faster than she had ever done since the day she was launched. As far as could be seen, she was holding her own well in what had now become a dead-on stern chase.
Still the stranger showed no flag, and though Tremayne could hardly believe that a hostile cruiser and a couple of torpedo-boats would venture so near to the ground occupied by the British battle-ships, the fact that she showed no colours looked at the best suspicious. Determined to settle the question, if possible, one way or the other, he ran up the ensign of the Royal Yacht Squadron.
This brought no reply from the cruiser, but a column of bluish-white smoke shot up a moment later from the funnels of one of the torpedo-boats, telling that she had put on the forced draught, and, like a greyhound slipped from the leash, she began to draw away from the big ship, plunging through the long rollers, and half-burying herself in the foam that she threw up from her bows.